LiNbO₃ :Pr³⁺ : A Multipiezo Material with Simultaneous Piezoelectricity and Sensitive Piezoluminescence

Red-emitting piezoluminescence (elasticoluminescence) is achieved by doping rare earth Pr³⁺ into the well-known piezoelectric matrix, LiNbO₃ . By precisely tuning the Li/Nb ratio in nonstoichiometric Li _x NbO₃ :Pr³⁺ , a material that exhibits an unusually high piezoluminescence intensity, which far exceeds that of any well-known piezoelectric material, is produced. Li _x NbO₃ :Pr³⁺ shows excellent strain sensitivity at the lowest strain level, with no threshold for stress sensing. These multipiezo properties of sensitive piezoluminescence in a piezoelectric matrix are ideal for microstress sensing, damage diagnosis, electro-mechano-optical energy conversion, and multifunctional control in optoelectronics.